This application is a 371 of PCT/EP02/08012 filed Jul. 18, 2002.
This invention relates to a new emulsifier compound with particular contents of fatty alcohols, ethoxylated fatty alcohols and selected oil and wax components and to the use of the emulsifier compounds for the production of cosmetic and/or pharmaceutical preparations.
Consumers expect cosmetic skin- and hair-care emulsions to satisfy a range of requirements. Apart from the cleaning and skin-/hair-care effects which determine the intended application, value is placed on such diverse parameters as very high dermatological compatibility, elegant appearance, optimal sensory impression and stability in storage. Some of these features, such as dermatological compatibility for example, can largely be objectively determined by the cosmetic chemist. However, when it comes to sensory impression, evaluation by volunteers is, ultimately, always subjective.
From the emulsion technology perspective, it is particularly important to provide emulsifiers and emulsifier combinations which produce fine-droplet and storable emulsions. Accordingly, there is always interest in the development of new emulsifier combinations which enable particularly stable, fine-droplet emulsions to be formulated. Reference may be made in this connection to the articles by A. Ansmann [Seifen-Öle-Fette-Wachse, 117, 518 (1991)], C. Cabeta [SÖFW-Journal, 120, 162 (1994)], P. Hameyer [SÖFW-Journal, 121, 216 (1995)] and, in particular, A. Wadle [Parf. Kosm. 77, 250 (1996)].
Although the expert knows of measures by which, in principle, fine-droplet and storable emulsions can be obtained, known emulsions are still not entirely satisfactory due to the choice of emulsifiers used. Emulsions are normally stabilized by a combination of emulsifiers. The self-emulsifiable mixtures based on fatty alcohols known, for example, from EP 0 553 241 (SEPPIC) or WO 97/18033 (fatty alcohol/alkyl polyglycoside mixtures) are often used for this purpose. The emulsifier mixtures obtainable under the names of Cetomacrogol® Emulsifying Wax (British Pharmacopeia), Cire de Lanol® CTO (Seppic S.A.), Sinnowax® AO (Cognis France, S.A.), Promulgen® D (Amerchol) are mentioned solely as examples of the fatty alcohol/fatty alcohol ethoxylate combination. Emulsifier mixtures based on fatty alcohol/alkyl polyglucoside/partial glyceride are known from International patent application WO 92/07543.
The emulsifier mixtures commercially available at the present time are often unsuitable for the production of low-viscosity o/w emulsions for which there is presently an increasing demand on the cosmetics market. Besides poor emulsion stability, changes in viscosity often occur during storage, particularly at elevated temperatures. At the same time, viscosity is often dependent on the shear rate in the industrial production process, so that products with different viscosities are obtained from different production plants. Such variations are not acceptable in the manufacture of cosmetic products or to the consumer.
Accordingly, the problem addressed by the present invention was to provide emulsifier mixtures (compounds) for the production of cosmetic products, more particularly thinly liquid low-viscosity o/w emulsions, with which it would be possible to obtain stable emulsions whose viscosity would not be affected by the shear rate during production and would not change even during storage under temperature stress (−5 to 50° C.). In addition, the emulsifier mixtures would have good skin-care effects and improved sensory properties that would allow the production of sensorially “lights” products. Another problem addressed by the invention was to provide emulsifier mixtures that would enable the formation of microfoam on the skin—known among experts as “white residue”—to be reduced. A further problem addressed by the invention was to provide emulsifier mixtures that would enable stable emulsions with a high salt content to be produced.